Quaternary bismuth alloy



Patented May 6, 1952 QUATERNARY BISMUTH ALLOY Oscar N. Carlson and Harley A. Wilhelm, Ames, Iowa, assignors to the United States of America as represented by the United States Atomic Energy Commission N Drawing. Application December 13, 1949, Serial No. 132,797

Claims. 1

This invention deals with a bismuth alloy and in particular with a quaternary alloy containing bismuth, lead, tin and gallium.

It is an object of this invention to provide an alloy which is characterized by a low melting point to be suitable as a liquid coolant.

It is another object of this invention to provide an alloy which is characterized by a low degree of corrodibility.

It is still another object of this invention to provide an alloy which is characterized by a low reactivity with water.

It is also an object of this invention to pro- Vlde an alloy which is characterized by a low neutron capture cross-section.

These and other objects are accomplished by providing an alloy consisting substantially of bismuth, lead, tin and gallium. Examples of suitable ranges in which the ingredients may be present in order to obtain a suitable composition having the above-listed properties are the following: 35-55% by weight of bismuth, -40% by weight of lead, 15-35% by weight of tin and 310% by weight of gallium. The preferred ranges of the ingredients are from 40-50% of bismuth, from 2l-31% of lead, from 16-31% of tin and from 5-8% of gallium.

In the following, a few examples are given for the purpose of illustrating the invention.

Example I An alloy was prepared which contained 40 parts by weight of bismuth, 21 parts by weight of lead, 31 parts by weight of tin and 8 parts by weight of gallium. When the solid alloy was heated for the purpose of determining the melting point, a melting range from 95-104 C. was ascertained. When cooling the melted alloy, a freezing range of from 86-95 C. was observed. This alloy was not based on the eutectic bismuth-tin-lead alloy, and it is therefore evident that also in the instant case the gallium had a considerable reducing efiect'on the melting point, since the ternary alloy, without the gallium, not being the eutectic composition, has a higher melting point than that of the eutectic, which is 96 C.

Example III Ninety-five percent of the ternary bismuthlead-tin eutectic and 5% gallium were mixed and heated whereby a homogeneous alloy was obtained containing 47.5% bismuth, 30.4% lead, 17.1% tin and 5% gallium. This alloy had a melting point of 84 C. which shows that the use of 5% (based on final alloy) gallium lowered the melting point by 12 C.

The alloys of this invention may be produced by any method customary in the art. On account of their low melting point, they are excellently suitable for use as coolants and due to their low neutron capture cross-section, they are particularly advantageous when used as coolants in atomic power piles and the like.

It will be understood that this invention is not to be limited to the details given herein but that it may be modified within the scope of the appended claims.

What is claimed is:

1. An alloy consisting of from 35-55% by weight of bismuth, from 15-40% by weight of lead, from 15-35% by weight of tin and from 3-10% by weight of gallium.

2. An alloy consisting of from 40-50% by weight of bismuth, from 21-31% by weight of lead, from 16-31% by weight of tin and from 5-8% by weight of gallium.

3. An alloy consisting of 47.5% bismuth, 30.4% lead, 17.1% tin and 5% gallium.

4. An alloy consisting of 46.7% bismuth, 29.9% lead, 16.8% tin and 6.6% gallium.

5. An alloy consisting of 40% bismuth, 21% lead, 31% tin and 8% gallium.

The following references are of record in the file of this patent:

UNITED STATES PATENTS Name Date Austin May 17, 1938 Number 

1. AN ALLOY CONSISTING OF FROM 35-55% BY WEIGHT OF BISMUTH, FROM 15-40% BY WEIGHT OF LEAD, FROM 15-35% BY WEIGHT OF TIN AND FROM 3-10% BY WEIGHT OF GALLIUM. 